The present invention generally relates to antennas that are mounted and employed onboard, for example, spacecraft or satellites. The present invention more particularly relates to frameworks or systems for deploying such onboard antennas while the spacecraft or satellites are in outer space.
Reflector antennas are commonly mounted and employed onboard spacecraft for sending and receiving electromagnetic waves within the radio frequency (RF) spectrum for communicative purposes while the spacecraft are in outer space. Although different types of reflector antennas may be utilized for such purposes, a commonly used antenna is a rib-supported reflector antenna. In a rib-supported reflector antenna, a framework or system of ribs is utilized to suspend, shape, and position a flexible mesh or screen made of RF energy reflective material. One significant advantage in utilizing such a rib-supported reflector antenna is that large-aperture antennas with sizeable diameters of up to 10 meters and more may therewith be implemented.
To successfully employ such a sizeable rib-supported reflector antenna onboard a spacecraft in outer space, the antenna must first generally be stowed in a folded, collapsed, or other reduced-volume configuration so that the antenna fits within the overall launch envelope of the spacecraft upon takeoff and initial transit into outer space. Once the spacecraft reaches outer space or its intended orbit, the rib-supported reflector antenna may then be unfolded, expanded, or spread out to thereby deploy the antenna into full volume for operation and service.
To successfully deploy a rib-supported reflector antenna in such a manner, its associated framework or system of ribs is typically unfolded, distended, or erected via a means that is, according to convention, largely electromechanical in nature. For example, in one known antenna deployment system, one or more electro-mechanical motors or actuators with associated drive cables are utilized to drive the unfolding, distension, and erection of a framework or system of ribs for a rib-supported reflector antenna. Also, in this same known system, the framework or system of ribs itself includes numerous metallic hinges and/or sliding joints that interconnect the ribs together to thereby further facilitate overall antenna deployment.
Although such a conventional electro-mechanical system can be effective in successfully deploying a rib-supported reflector antenna, the mechanisms can be heavy and also complex to use and operate. In particular, such a system with motors, actuators, pulleys, cables, hinges, sliding joints, and the like can be somewhat massive both in terms of weight and size. Any such excess weight or size is generally undesirable onboard a spacecraft, for it generally necessitates an accommodating increase in launch thrust or launch envelope size. In addition, such a system can also be complex in terms of both the positioning and the cooperative functioning of its many interrelated parts, thereby giving rise to potential reliability concerns and increases in expenses for components.
In light of the above, there is a present need in the art for an improved framework or system that is lighter in weight, less expensive, and less complex than known deployable antenna systems. In addition, there is also a present need for a system that can successfully deploy a rib-supported reflector antenna in outer space with minimal to no assistance required from, for example, electromechanical motors or actuators.